


Eliminating a Tactical Disadvantage

by Strings (fangirlgeekout)



Series: Discovery & Laughter [1]
Category: Supernatural
Genre: Fluff and Humor, M/M, Pre-Slash, Season/Series 05, TWP - Tickles Without Plot, Tickling, Ticklish Castiel
Language: English
Status: Completed
Published: 2014-10-11
Updated: 2014-10-10
Packaged: 2018-02-20 17:04:22
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 4,312
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/2436302
Author URL: https://archiveofourown.org/users/fangirlgeekout/pseuds/Strings
Summary: <blockquote class="userstuff">
              <p>Castiel has been disconnected from his holy recharging cable, and is in denial about his vessel’s human vulnerabilities.</p>
<p>---</p>
<p>  <i>Castiel tightened his grip on the bed coverings, trenchcoat splayed out under his back. An uncomfortable sound accompanied his pained expression. This had been a terrible idea.</i></p>
<p>  <i>Ten wriggling fingertips ghosted across his lower ribs, just below the pushed-up hem of his shirt. Cas pinned his lips shut, but failed to suppress a gutteral snort and the subsequent huffs of air that escaped through his nose. His stomach convulsed in its instinctual attempt to dodge the feather-light touches. He could feel his vessel’s nerve endings firing, the impulses sparking up his spinal cord and into his brain. He commanded his arms to stay put on the mattress, but they were having trouble obeying.</i></p>
            </blockquote>





	1. Chapter 1

**Author's Note:**

> This was my first-ever fanfic; please excuse the rampant POV-swapping. Inspired by [Castiel's shoulders](http://nerdstrings.tumblr.com/post/67554296787/mishawinsexster-lets-all-just-take-a-moment-to) and [Dean's internal monologues](http://mostly10.com/post/17968883730/nobody-does-internal-monologues-like-dean-does).
> 
> Originally published Nov 2013 on [Tumblr](http://wordstrings.tumblr.com/post/67700212269/eliminating-a-tactical-disadvantage-part-1) as a two-part fic.

Castiel tightened his grip on the bed coverings, trenchcoat splayed out under his back. An uncomfortable sound accompanied his pained expression. This had been a terrible idea.

Ten wriggling fingertips ghosted across his lower ribs, just below the pushed-up hem of his shirt. Cas pinned his lips shut, but failed to suppress a gutteral snort and the subsequent huffs of air that escaped through his nose. His stomach convulsed in its instinctual attempt to dodge the feather-light touches. He could _feel_ his vessel’s nerve endings firing, the impulses sparking up his spinal cord and into his brain. He commanded his arms to stay put on the mattress, but they were having trouble obeying.

Dean’s fingers continued their slow, steady exploration along Castiel’s sides, circling back up to his ribcage and repeating their path a second time. The combination of the hunter’s slightly calloused hands and their unexpectedly delicate touch was maddening, and Cas found himself wanting to squirm straight out of his skin. He was swiftly losing the battle against the mystifying urge to laugh. With eyes scrunched shut, his lips broke into a tight, wide grin and he buried the side of his face into the pillow. Dean chuckled and continued his distracting progression down the angel’s torso, both hands converging on his lower belly just above his belt.

"Come on, Cas, don’t fight it," Dean drawled from his perch on his victim’s thighs. He upped the stakes and started scribbling gently with his fingernails. A choked sound forced its way out of Cas’ throat. "Almost there," Dean grinned.

This had been a really, _really_ terrible idea. He should not have agreed to Dean’s suggestion.

—-

_With Castiel’s heavenly batteries running low, Dean had proposed that he stay back on their next hunt. Cas wasn’t having any of that. They’d argued - although one couldn’t really call it a proper argument with the way the angel kept his impeccable cool the whole time. That only seemed to irk Dean further, and Cas couldn’t quite figure out why._

_"Dean, why are you getting angry?"_

_"Because-" he huffed and made a frustrated gesture - "because you… I don’t want you getting hurt out there. And you don’t really seem to care if that happens."_

_Cas cocked his head. “My vessel is expendable if I need it to be. I won’t allow its weakness to keep me from doing what must be done, if that is what you are concerned about.”_

_"Oh, so you’re expendable now?!" Dean jabbed a finger at the angel’s chest. "I really don’t think you understand-"_

_"That is not what I meant," Cas retorted, while his vessel inexplicably dodged backward. "I would like to continue existing in this manner to assist you, but my well-being does not take priority."_

_"Well, I’d like you to continue existing, too. But you don’t seem to have a full grasp on how your ‘expendable vessel’ might cause us some issues." Dean’s eyes narrowed as he jabbed again. And again, Cas jerked back. He glanced down at his body with a hint of confusion before opening his mouth to respond._

_"See, like that!" Dean fought off a smile, maintaining an expression of faux irritation._

_"Like what?"_

_“…You’re not gonna believe me unless I show you.”_

_—-_

Cas’ arms twitched uncontrollably as he tightened his death grip on the blankets. “Where have we- _mmph_ \- almost arrived?” he managed, the pillow muffling his words.

"At _you_ realizing that you’re not a holy friggin’ robot and _sometimes_ you won’t be able to control everything you do.”

To his endless frustration, Cas was starting to comprehend how correct Dean was. This reaction had not been what he was expecting of his vessel. There was no reason for him to be smiling in this situation. And why was his breathing so difficult to regulate? He’d never had to think about it before, and he was starting to worry that something was going wrong with this body. Maybe Dean had a point.

His thoughts vanished in the next instant, as he jerked and tried (and mostly failed) to not arch up while Dean’s hands spidered rapidly up his sides again, working further back on his ribcage. They hit a spot that made him jump, which did not go unnoticed by the attuned hunter balanced atop him. Dean smirked and dug his fingers in.

"AAAH!" Cas lost his iron grip and his elbows came slamming inward on the hunter’s hands.

"Aaand jackpot," Dean announced triumphantly.

Helpless cackles filled the motel room. Cas twisted and bucked, unable to focus enough to unseat his tormentor. Nothing mattered more than escape, but he found it impossible to coordinate his movements.

“WhyHEHE can’t I- AGH!” His chin snapped down when the unbearable sensation jumped up to his collarbones and the tops of his shoulders, and he fought for a grip on the invading hands, snorting all the while.

Dean laughed. This was the most… _human_ he’d ever seen Cas. And if he was honest, it was pretty damned adorable. “I don’t know if you’re just low on mojo or what, but I hate to break it to you - you’re ticklish.”

“How is this-” Cas’ snorts morphed back into full laughter when the fingernails skittered back down to his stomach - “poHAHAHAssibly relevant to a- ahaHA- a hunt?”

“Pff. You talk too much.” Dean batted away Castiel’s poor attempt to protect himself. The guy had to be _seriously_ low on power - moreso than he’d originally suspected. Not good. But then again, how often would he get the chance to tickle the crap out of an angel? And Cas’ laugh was definitely one of the best sounds he’d ever heard. Deep and not quite so gravely as expected, with bright spikes of clarity whenever he hit a good spot.

Dean worked across every bit of skin he could reach, swatting past the flailing hands, making sure to linger in the places that seemed to drive Cas’ laughter up another notch. There was that spot toward the back of his ribs, the crook where his neck met his shoulders, either side of his bellybutton, right under the lowest rib on his left side (but not so much on his right), and all along his pant line. Dean was scrabbling over this spot for the third time when he noticed how labored Cas’ breathing had become. He decided to give him a break and tapered off his attack.

It took a moment for Cas to come down from his laughter. Chest heaving, he wrapped his weakened arms around himself and cracked his eyes open. “Do all human bodies… react like this? To… tickling?”

Dean noticed the slight hoarseness in his voice and felt a tiny stab of guilt. He shrugged. “Most of them, I guess.”

"I have never witnessed this in a battle scenario. However, if you are concerned that this weakness may endanger me, I will trust your judgement."

"Well, it’s… it’s not exactly _dangerous_. I’m just trying to prove a point, okay?” He was about to let the angel up when he noticed a fleeting glint in the blue eyes beneath him. _Uh-oh._ Dean could tell Cas was tired, but not wiped out nearly enough to be unable to launch a curious counter-attack with this new information. The earlier pang of guilt was swiftly replaced with a desperate bid for self-preservation. “But, uh… it’s not necessarily a no-win situation,” he stammered out. _What the hell are you talking about?_ his brain protested.

_Shut up, I’m trying to save us._

And there was that signature head tilt again. Thank God.

"It can be overcome?"

"I, uh… Not exactly."

"Please explain."

Dean pursed his lips, trying to figure out where he was going with this. “I mean… It’s better to know exactly what your weaknesses are instead of going in blind, right?”

"Yes, Dean. I am a soldier, remember?"

For a moment, Dean wasn’t sure if Castiel was trying to be helpful by resupplying established information, or if he was getting snarky.

"…Right. So, I’m just trying to help you understand your, uh, _susceptibilities_. There are a couple more you should know about.”

"Other than this tickling?"

Dean eyed the body lying beneath him. “Heh, yeah.” _WHAT?!_ “Uh, I mean - you’re not familiar with any of your vessel’s other weak spots, so… you should know, right?”

Cas stared calculatingly at him for a moment before answering. “That _would_ eliminate a tactical disadvantage.”

Dean grinned. “Yeah.” He shifted to the side, temporarily freeing the angel’s legs. “You’ll have to turn over. And lose the coat.”

The withering look of suspicion was nearly comical in its intensity. _Stick to the plan, Dean._

_What plan? Tickle the snot out of him until he’s too exhausted to turn the tables? Not exactly a permanent solution._

_You got any better ideas?_

Never breaking eye contact, Cas smoothly sat up and shed his trenchcoat.

"The jacket, too." And before he could stop himself, "Shirt wouldn’t hurt either." _Christ, shut UP._

"I do not see how that is relevant." But he complied anyway, shrugging out of the suit jacket and unbuttoning his shirt. The garments were laid aside and Cas repositioned himself on his stomach, arms lying awkwardly along his sides.

Dean quirked an eyebrow. “You can get a bit more comfortable if you want. Here.” He grabbed one of the pillows and flopped it down near Cas’ head.

The muscles in the angel’s shoulders rolled under the surface of his skin as he reached out to pull the pillow under his head and chest. He experimentally wrapped his arms around it, making a few adjustments before falling still. “Thank you, although I doubt this version of the experience will be any more comfortable than the last.”

"Aw, it wasn’t that bad, was it?"

"Yes."

"Relax. I’ll go easy on you."

"Nothing about this is relaxing."

Dean swung his leg over Castiel’s lower back and settled in with a predatory smile. “Try to keep your arms up there like before. I really don’t need to get kidney-punched by an angel.”

"I will try. I do not wish to injure you."

"Yeah, not yet anyway," Dean muttered under his breath. He paused for a moment, studying the form presented to him. Cas’ back was lean, the dip of his spine leading up to corded shoulders. His biceps disappeared under the pillow beneath his head. Suddenly Dean recalled the image seared into his mind - the massive shadow of wings that had stretched across the expanse of the barn when Castiel had first appeared to him. His eyes searched along the sculpted upper back, trying to determine if they really existed there. He reached toward the space between the shoulder blades, briefly lost in wonder.

Cas craned his head up to peer sideways at the unusually quiet hunter on his back. Dean jerked his hand back, mouth opening and closing once as he collected himself. He cleared his throat. “Okay. So.”

Cas steeled himself. _Uncomfortable_ was an accurate description of this situation. Willingly opening himself to attack went against his millennia of training. His evident inability to maintain control of his vessel during such an attack was worrying. However, besides the irregular breathing (and even _that_ passed a short while after), there seemed to be no adverse effects that accompanied being tickled. And, he admitted, the sensations themselves were not entirely unpleasant. It was mostly the urge to get away that was troublesome.

Then there was the additional point that Dean appeared to enjoy the reactions it elicited. Dean didn’t smile very often, and Cas found that he liked seeing the hunter’s face free of worry every once in a while.

He felt a pair of hands come to rest high on his waist. He tried not to flinch.

Dean’s smile was audible in his voice. “Alright, so we already know about this spot-” he wriggled his fingers in place, and was rewarded with a twitch - “and this-” higher on Cas’ ribcage, another twitch - “so let’s try…”

The hands broke contact, and Cas suddenly felt an unexpected twinge of anxiety. He hadn’t taken into account how this position left him unable to see his attacker’s movements. His skin abruptly tingled with heightened awareness.

"…Here." Scrabbling at the back of his neck. His shoulders instantly rolled up without being directed to do so. Cas shoved his face into the pillow as if it would stifle the undesired breath-reaction. The sensation spread outwards along his tensed shoulders, and he was dimly aware that he couldn’t hunch an already-hunched body part, although that didn’t seem to stop him from trying.

The fingers wandered out past his shoulders and crawled up the outer edge of his arms. The tightness in his lungs eased a little, but was replaced with an unfamiliar wave of cool electricity that washed down from the base of his skull. A subtle undulation rushed down his spine, riding the crest of the thrill.

The hands paused for a beat, then repeated their motion up his triceps. The wave happened again, and he felt his skin prickle. _That_ was _definitely_ not unpleasant. He was about to ask what it was when he heard Dean chuckle.

"I had no idea angels could get goosebumps." Then, so quietly Cas almost couldn’t hear, "Filing that one away for later."

Cas jumped when the fingertips slid down into his underarms. His breath didn’t even have time to hitch before the giggles came streaming out. _Giggles._ His arms screamed to protect himself and he grabbed forcefully at the upper edge of the pillow. The light scribbling of fingernails in the hollows was almost too much. Castiel’s entire body trembled with the effort to keep his arms in place. If this continued, loss of control was inevitable. And he’d promised he wouldn’t punch Dean. Okay, didn’t exactly promise, but implied. That wouldn’t normally count, but here it seemed wrong if it didn’t.

"DeheheHEHEHEAN!"

"Right here," an amused voice answered. The fingers didn’t slow.

"I- hehehehe- I CAHAN’T-" Cas squeaked, giggles surging when the pace increased. His elbows jerked partway down, and the tickling fingertips finally backed off a little.

"Yes, you can." He could hear Dean’s smile again. The touch changed to long, feathery strokes that trailed up his triceps again. The shiver happened a third time. Cas hummed contentedly and slid his arms back up under the pillow, deciding not to overthink his reaction the welcome difference in sensation. The pleasant touch continued for a few blissful seconds, before leaping back down into his armpits with a vengeance.

"NAAHAHAhahaha!" Cas nearly convulsed when the treacherous hands pinched and dug at the flesh. He curled his forearms, bringing the pillow to his face instead of the other way around. His muffled cackling was infectious. Dean had already been on the verge of losing it himself, but the way Cas kicked and screeched into the pillow was the funniest thing Dean had seen in weeks, and he burst out laughing, dropping his hands to the mattress to support himself.

Cas flopped down, panting. The hunter’s laughter was loud and close, and it would have been a bit galling in any other situation. But this… this was almost enjoyable. For as little as Dean smiled, he laughed even less. And if his laughter was even just a fraction as distracting as Castiel’s own, it was a much-needed break from their apocalypse-filled lives.

He turned his head to look tiredly up at his assailant. Dean’s shoulders were shaking, eyes crinkled shut as he barely managed to prop himself up with a hand planted on either side of Cas’ chest. After a moment, he took a long, shaky breath and sat upright, wiping at his eyes.

"Oh my God," he groaned, pressing an arm across his stomach. He looked back down at the rumpled mess of an angel that graced the bed beneath him. "That was awesome."

Cas took a breath, then smiled. A real, non-tickle-induced smile. It truly was good to see Dean happy.


	2. Chapter 2

Dean wiped at his face with his hands, trying to soothe the sore muscles in his cheeks. He huffed one final laugh and looked down at the bare top half of the flustered angel lying face-down beneath him on the motel bed.

Cas took a breath, calming the remnants his own laughter. Dean had nearly tickled him straight out of his skin. It had been framed as an exhibition of his vessel’s increasingly-human vulnerabilities while he was cut off from Heaven’s power. And it had been quite convincing.

Cas turned his head sideways on the pillow to look up at his… _friend_ seemed to be the appropriate word. He hesitated only for a second.

"I don’t believe you are finished."

Dean blinked. “…What?”

"This vessel appears to be sensitive in some way to each area you’ve touched. There are still several areas you have not… demonstrated yet. I do not wish to be caught by surprise in an undesirable situation."

Part of Dean really wanted to ask if the angel found this a _desirable_ situation, but he settled for, “Jeez, Cas, don’t you think you’ve had enough?”

The angel was still flushed slightly pink, his breathing pattern just starting to return to normal. “Yes, but I doubt my resolve to again subject myself to this once I have fully recovered. This might be the only chance you get.” He turned back to the pillow. “Besides, I am fatigued and less likely to hurt you by accident. Tactical advantage, Dean.”

It was Dean’s turn to cock his head. “Are you sure?”

"Don’t afford me the opportunity to change my mind." Castiel pulled his arms from beneath the pillow that supported his head and stretched out toward the headboard, straightening his elbows with a barely audible pop. He held the stretch for a few seconds to dislodge the feeling of stiffness. "Besides, you’re clearly enjoying yourself."

Dean froze, momentarily at a loss for words. “What?” he repeated.

The angel rolled his bare shoulders to work out the tension that had settled in his vessel’s hunched muscles. “You rarely have occasion to laugh, Dean.” He resettled himself and drew his arms back under the pillow. “It’s good for you.”

"I…" The hunter sat back, unsure of how to respond. "I could say the same for you, I guess."

"I guess," came the gravely echo.

The silence stretched for a few seconds. Dean suddenly clapped once, snapping them out of the uneasy moment. “So, my _only chance_. Guess I’d better make the most of it.”

He rebalanced himself slightly lower on Cas’ bare back. “Keep those hands to yourself, angel boy,” he reiterated, “Same as last time. No punching.” By way of encouragement, he gently drew his fingertips across the relaxed triceps that peeked out from under the pillow, and was rewarded with a pleased hum. _Damn, that’s distracting._ His eyes trailed down, following the curve of the spine. He blinked and forced himself to refocus.

"We left off _here_ , I believe…”

Cas jolted at the fingernails that skittered into his armpits. The giggles rolled freely out and he squirmed into the mattress. This time he wasn’t even attempting to stifle his reactions, it seemed. Dean wasn’t sure what to make of that, but didn’t spend much time thinking about it. He lingered in that spot for a moment, experimenting with how to draw out different pitches in Cas’ giggling. He _was_ enjoying himself.

_So sue me._

His hands traveled downward and inward, tickling a circuitous path across the back of the angel’s ribcage, then kneading down the muscled sides, listening for the changes in laughter to clue him in to the good spots. He noticed how Cas’ arms were slipping further out from beneath the pillow, but that didn’t really matter. If Cas hadn’t been able to effectively defend himself when face-to-face, he’d hardly be able to fight back in this position.

The electric impulses riding up Castiel’s spine were relentless. He was systematically losing control. It was a completely unfamiliar experience and a little bit terrifying. Or, at least, it would be, but he knew Dean would never hurt him. The conflicting feelings of safety and vulnerability were… confusing.

A spike of sensation jolted his entire body. Dean had worked his fingers under Cas’ hips, wriggling them in the tight space between the bones and mattress. Cas _squealed_.

"N-nohoho!" he gasped. Part of him - the part that wasn’t concentrating on bucking uselessly - realized that was his first actual protest during this whole ordeal.

"Hmm, you’ve really gotta keep an eye on this spot, Cas," Dean deadpanned, fingers clawing into the flesh. The body trapped beneath him writhed, cackling. "If a monster went for you here, I’m sorry to say you’d probably be toast."

One arm finally freed itself from under the pillow and swung back at him. He dodged it and laughed. “Watch it, Cassie, you don’t wanna piss me off.”

"I will SMITE YOUhohohou!"

Dean reflexively grabbed the angel’s wrist with one hand and pinned it to the mattress.

"Threats?" he growled playfully, continuing his assault with his remaining hand. "You have no idea what you’re messing with, angel." A muffled string of Enochian flew back at him.

"I have no idea what that meant, but I’m sure it was disparaging."

The other arm came flinging back in his direction. He caught that wrist as well. “You have much to learn, young padawan,” he grinned. With a surprisingly minimal amount of resistance, he shoved each arm down on the bed so he could keep them pinned with his knees. He silently breathed relief over how exhausted Cas was. “Now you’re screwed.”

Cas couldn’t get enough leverage to lift his head, but he turned his face to the side and glared as best he could. There were still some aspects of facial expression he didn’t understand, but he was positive that his residual panting and lingering smile undermined the seriousness he meant to portray.

"Aw, you’re adorable." The words fell out of Dean’s mouth before his brain could filter them.

Castiel’s gaze dropped to the pillow.

_Shit._ “I, uh…” Dean averted his eyes and puffed air out his cheeks, suddenly hyper-aware of the body between his thighs. Which hadn’t moved. He ventured a furtive glance down.

Those piercing blue eyes were staring at him again. God, they were so blue. That couldn’t just be the vessel, right? Nobody’s eyes looked like that.

_Get a grip._

"You appear to be uncomfortable," Cas intoned.

_Yes, help._

_No, I’m **very** comfortable._

"…I don’t… Are you?"

"No." Cas craned up to look down at his trapped arms. "Physically, perhaps."

"Oh! Sorry-" Dean lifted one knee, but the released hand didn’t move.

"You’re attempting to give me far more leeway than I would afford you if our positions were reversed."

Dean’s jaw dropped. “…I’m sorry, _what_?”

"Do I really need to repeat the phrase ‘tactical advantage’ again?"

"So you’re saying… Are you telling me that you would…" He shook his head with an incredulous smile. "Oh, it’s _on_.”

Cas felt the pressure return on his wrist at the same instant ruthless fingers jammed into his underarms.

"GAAAHAHAhahaha!" The light spidering from earlier was gone, replaced by merciless scratching and digging. His shoulders jerked violently, as much from helpless laughter as from his arms trying to escape their human restraints. Being forcibly caught was _much_ worse, he subconsciously realized. The conscious part was concerned with getting away, and nothing else. “DEHEHE _HEHEHEAN_!”

There was a warmth at his neck. He started, suddenly aware of the hunter’s face leaning in close. A dark voice growled in his ear.

"How’s this for tactics? I’m gonna tickle you until you scream for mercy. And _then -_   _maybe -_  I’ll _think_ about giving it to you.”

—-

Castiel was dead weight on the bed, gasping for air. His limbs felt boneless. He could never recall feeling such complete physical exhaustion in a vessel before.

The mattress bounced as Dean flopped down beside him, looking exceptionally proud of himself.

"You are one stubborn sonofabitch," he grinned. "I don’t think I’ve ever even gotten Sammy that good. For a minute there, I thought you might actually pass out before giving up and asking me to stop."

"I… _did_ … ask you… to stop.”

"Yeah, _eventually_. You’re lucky I was starting to feel bad.” He reached down and tweaked the back of the Cas’ knee. Cas whimpered.

"Alright, no more," Dean smiled. Without really thinking about it, he scooted closer and tossed an arm over the angel’s back. He frowned slightly at the reactive flinch. "Sorry. Went a little overboard, huh?"

Cas didn’t answer. He would have done some scooting of his own, except he honestly couldn’t find the strength to move. He sighed, allowing himself to enjoy the warmth of Dean’s not-quite-hug. This time the silence wasn’t uneasy.

Dean was nearly drifting off when Cas said, “You didn’t follow through on your implied threat.”

"Hmm?"

"Of not stopping."

"…It’s called _intimidation_. I wasn’t trying to… Dude, I wouldn’t actually torture you.”

"In a combat situation, you should not make threats you are not prepared to follow through on."

"Excuse _me_ , Mister ‘I-Will-Smite-You.’ You know this stopped being about ‘combat’ pretty early on, right?”

"Of course. I was simply stating-"

“ _Of course_ ,” Dean mocked, cutting him off. “…Wait a minute.” His eyebrows furrowed. “You _encouraged_ me.”

"Yes."

Dean gaped. “Why?”

"Your point about knowing my vessel’s weakness was valid. I am indeed not a ‘holy frigging robot.’ And as I said before, it’s good for you to laugh." He paused. "I like when you laugh."

The hunter’s lips tugged up at the corners. “Well, I like that you’re not a robot.”

Castiel smiled back. He used what little energy he’d regained to edge closer to Dean. He felt the hand at his back move up and start gently stroking his upper arm.

This hadn’t been a terrible idea at all.


End file.
